The European Union's enlargement commissioner has urged Bosnia-Herzegovina to implement concrete reforms if it wants to join the bloc, warning that the window to becoming a member could close.

Johannes Hahn said on December 4 that Bosnia had not made any of the reforms or changes agreed with the EU and international creditors since the bloc accepted the Balkan state's membership application in September 2016.

"It is absolutely high time now to deliver on what has been agreed. Otherwise, the window can be closed again and this is not something we all would like to see," Hahn told a news conference after meeting political leaders in Sarajevo.

Bosnian Prime Minister Denis Zvizdic said he hoped that the country's political leaders will reach a compromise on outstanding issues by early January.

The ethnically divided country has so far not responded to the European Commission's questionnaire on its readiness to join the bloc.

The questionnaire is used by the commission as a tool to gather information necessary for forming an opinion on a country's capacity to comply with EU membership criteria.

Hahn urged government and opposition leaders to stop appealing to ethnic nationalism, and said the bloc would be looking for evidence of European values.

"Without that understanding one cannot make any progress," he said.

Since the Bosnian war ended in 1995, Bosnia has been split into two entities -- the ethnic Serb-dominated Republika Srpska and the Muslim-Croat Federation of Bosniaks and Croats.

The two entities are linked by joint state-level institutions, including a tripartite presidency that must reach consensus before decisions can be made.

Hahn said he understood the "complexity" of the situation, but insisted that there was no more time for any "excuses."

With reporting by Reuters

RFE/RL's Balkan Service promotes the values of democracy, human rights, and freedom of expression in a region where genuine media freedom remains elusive and where many media outlets remain divided along ethnic lines.